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| Titel |
Mountain waves and inertia-gravity waves during T-Rex experiment |
| VerfasserIn |
H. Teitelbaum, M. Moustaoui, A. Mahalov |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250021384
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| Zusammenfassung |
| T-Rex observation campaign took place in Owens Valley during March and
April 2006. Among other measurements, we are interested in radio
soundings that took place on 25 March at 08 UTC (R1) and 01 April at
7.50 UTC (R2) both at 36.48 S, 118.44 W. These radio soundings include
profiles of the horizontal wind components and temperature. They are
supplemented by ECMWF analysis, and simulations using the WRF model.
Above 16 km altitude, a wavelet analysis applied to the observed
profiles shows a wave with a vertical wavelength around 3 km.
On the basis of this analysis, the profiles are filtered around the
observed wavelength. The results show a wave with a long wavelength in
the troposphere and a short one in the stratosphere, above a transition
region. Using the ECMWF analysis, we found that the jet has a V-shaped
pattern at 13 km altitude, above and close to the radio sounding
launching site. The cross-stream Lagrangian Rossby number also shows
values higher than 0.35. Other indications suggesting the presence of
ageostrophic flow are found at higher altitudes where the wave amplitude
reaches larger values.
The horizontal wind at 2-3 km altitude obtained using the mesoscale WRF
model shows that on 25 March, the relationship of the wave with respect
to the orography is more regular compared to the 1 April case. As a
consequence, the altitude-latitude cross-section of the vertical
velocity is more localized on 25 March. Furthermore, the vertical
wavelength is clearly identified in the vertical velocity for both
cases. In contrast to the vertical wind, cross-sections of the
divergence of the horizontal wind show that the wave amplitude in the
stratosphere is higher than that found in the troposphere. This
indicates the presence of inertia-gravity waves at higher altitudes. |
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